Save gallery from imagebam by its GID. It handles filename collisions by renaming.

imagebam_dl

#!/usr/bin/ruby

require "pry"
require "peach" rescue nil

gallery=ARGV[0].chomp("/")
page_num=1
gallery_id=gallery.split("/").last

%x{mkdir "#{gallery_id}"}
Dir.chdir(gallery_id)



begin
  ret=%x{curl -s -L #{gallery}/#{page_num}}
  links=ret.scan(/href\=[\'\"](https?\:\/\/www\.imagebam\.com\/image\/[a-f0-9]+)[\'\"]/i).flatten.uniq
  
  if links.respond_to?(:peach) then 
    links.peach(4){|l|
      page=%x{curl -s -L "#{l}"}
	  md=(/href\=[\'\"](https?\:\/\/[0-9]+\.imagebam\.com\/download\/.*?\/[0-9]+\/[0-9]+\/.*?)\?download\=1[\'\"]/i).match(page)
	  url=md[1]
	  STDERR.puts "#{l} -> #{url}"
	  fname=url.split("/").last
	  if !File.exists?(fname) then
	     %x{curl -# -L -O -J "#{url}"}
	  else 
	     index=1
	     begin
	       extension=File.extname(fname)
	       new_fname=fname.chomp(extension)+"."+index.to_s+extension
	       index+=1
	     end while File.exists?(new_fname)
	     %x{curl -# -L "#{url}" > '#{new_fname}'}
	  end
    }
  else
    links.each{|l|
      page=%x{curl -s -L "#{l}"}
	  md=(/href\=[\'\"](https?\:\/\/[0-9]+\.imagebam\.com\/download\/.*?\/[0-9]+\/[0-9]+\/.*?)\?download\=1[\'\"]/i).match(page)
	  url=md[1]
	  STDERR.puts "#{l} -> #{url}"
	  fname=url.split("/").last
	  if !File.exists?(fname) then
	     %x{curl -# -L -O -J "#{url}"}
	  else 
	     index=1
	     begin
	       extension=File.extname(fname)
	       new_fname=fname.chomp(extension)+"."+index.to_s+extension
	       index+=1
	     end while File.exists?(new_fname)
	     %x{curl -# -L "#{url}" > '#{new_fname}'}
	  end
    }
  end
  page_num+=1
end while links.size>0
Dir.chdir("..")

Does not work on Linux with ruby 3.0.1p64 (2021-04-05 revision)
error:
<internal:/usr/lib/ruby/3.0.0/rubygems/core_ext/kernel_require.rb>:85:in require': cannot load such file -- pry (LoadError)
Did you mean? pty
from internal:/usr/lib/ruby/3.0.0/rubygems/core_ext/kernel_require.rb:85:in require' from imagebamdl.rb:3:in

'
`
idea how to fix it? @Konstantinusz
btw. another attempt in bash here